+/*
+ * Find an associated nfs write request, and prepare to flush it out
+ * Returns 1 if there was no write request, or if the request was
+ * already tagged by nfs_set_page_dirty.Returns 0 if the request
+ * was not tagged.
+ * May also return an error if the user signalled nfs_wait_on_request().
+ */
+static int nfs_page_mark_flush(struct page *page)
+{
+ struct nfs_page *req;
+ spinlock_t *req_lock = &NFS_I(page->mapping->host)->req_lock;
+ int ret;
+
+ spin_lock(req_lock);
+ for(;;) {
+ req = nfs_page_find_request_locked(page);
+ if (req == NULL) {
+ spin_unlock(req_lock);
+ return 1;
+ }
+ if (nfs_lock_request_dontget(req))
+ break;
+ /* Note: If we hold the page lock, as is the case in nfs_writepage,
+ * then the call to nfs_lock_request_dontget() will always
+ * succeed provided that someone hasn't already marked the
+ * request as dirty (in which case we don't care).
+ */
+ spin_unlock(req_lock);
+ ret = nfs_wait_on_request(req);
+ nfs_release_request(req);
+ if (ret != 0)
+ return ret;
+ spin_lock(req_lock);
+ }
+ spin_unlock(req_lock);
+ if (test_and_set_bit(PG_FLUSHING, &req->wb_flags) == 0)
+ nfs_mark_request_dirty(req);
+ ret = test_bit(PG_NEED_FLUSH, &req->wb_flags);
+ nfs_unlock_request(req);
+ return ret;
+}
+